Acoustical diaphragm



Aug, 28, 1923. 1,466,427

w. H. DRUMMOND AGOUSTICAL DIAPHRAGM File d Oct. ,30 191'? V A INVENTOR ATTORN E-Y Patented Aug, 28, 1923.

- Trs WILLIAM E. nn-oraivronn, or BELLEVIIILLE, new JERSEY, nests-non or 1 TO nLWoon JONES, OFNUELEY, 'NEW'JERSEY.

Fig.-

ONE-HALF AooUs'rIcAn DIAPHRAGM.

Application filed October 30,1917. Serial No. 199,227.

To all whomc't may concern: Be it known that I, FVILLIAM- H; DRUM- :uonn, a citizen vof the United States, and resident of Belleville, county of EssernState of New Jersey, have invented certaiirnew" "and useful Improvements in Acoustical Diaphragms, of which the following is a specification. r The present invention relates to the utilization of' theinner skin of trees, such as that of the poplar tree, the basswood tree, the tulip woodltree and that of such other trees and vegetable growth as may be found useful for the present purpose, and the production of an article of any desired thickness for use in thearts.

I have found that the inner skm of the poplar tree, for instance, when sub ected to moisture disintegrates into very fine films having strength enough to permit of their being handled. \Vhen washed and dried, an article is produced having considerable strength and useful in making di'aphragms for sound boxes of phonographs and micro-- The material also can be used in the manufacture of musical instruments, such as violin cases, horns, as for phonographs, organ pipes, sound boards of any.

description, because of its excellent resonant qualities. From its nature, the material is a non-conductor and is useful, therefore, as a dialectric in the electrical art.

The surface of the article when finished has a pleasing figure, and the material can be used in making of art objects and for decorating purposes. The material is more or less translucent, regulated by the thickness of the finished article and is useful as a lamp shade, for instance,

The material can be worked in the way that wood is worked, andv utilized in the,

making ofarticles, such as boxes, cases and receptacles, generally.

In the assembling of the articles for any desired purpose, any suitable means for supporting a layer or for binding layers together is used, such, for instance, as glue or shellac or collodion.

The use of the above material as a sub-v stitute for the mica or metal diaphragms in the sound boxes of phonographs and the like has given remarkable results, the tonal qualities of the records being accurately reproness is obtained.

duced, and the needle scratching being greatly reduced or eliminated altogether,

'1' have, therefore, illustrated'my; vinvert- 1 tion as applied to the manufactureifof diaphragmsfor sound boxes in the accompanying drawing, in which Figure 'lpis a surface -.elevat1on of. a diaphragm; Figure 2 1s '.a

side View of the diaphragm; Figure 3: is a disk of stiffening or supportmgmaterial;

F igure 4 is a side View o-fa diaphragm composed ofone of each ofthe materials shown in F igures 1 and 3; and Figure 5 1s anena film of the inner skin of the poplar tree,

and 2 is another film (Fig. 2), the two layers being ioined together by glue, or shellac.

While I have shown in Figure Q-only two layers of material, it is to be understood that the number of layers will. be multiplied, if desired, until an article of the desired thick The strength of the material is increased if the grains of the films are crossed, in the i assembling of the diaphragm.

For the purpose of further strengthening the diaphragm, a supporting or stiffening material, such as linen, silk, cotton, wirecloth or, a sheet of thin metal, perforated, if desired, shown at 3 (Fig. 3) is used and. faced with one or more layers of film, 1 (Fig. 4). V 1, are crossed when the additional strength of that arrangement is desired.

The preferred form of diaphragm is shown in Figure 5, where the supporting material, 3, is shown faced on both sides with a layer of film 1 and 2.' Otherlayers,

Here again, the grains of the films,

1 or 2 are added to oneside or to'both sides to obtain any desired thickness. this embodiment, as in the others, the grains strength. 1

If desired, the outer surfaces of the ma terial are coatedwith shellac for rendering the article moisture proof. In the stamping out of the article for use as diaphragms for phonograph sound boxes, I have found 1t advantageous to use polished dies, heated prior to the punching operation and at each punching operation to leave the die down of the films may becrossed with respect I to each other for obtaining additional 65 larged'side view of a diaphragm .w'lrentlie;-

and then cool off the die before raising it from the varticle. T his alternate heating and cooling, operation is repeated for each disk, When this is done, the article has a highly polished surface or surfaces I claim as my invention:

1. A diaphragm for sound boxes composed V of superposed Washed natural films 0t vegetable growth. 7 7

2. A diaphragm for sound boxes composed of a Washed natural film of vegetable growth and a layer of strengthening material. 1

3-. A"diaphragm" for sound boxes composed of Washed natural fihns of vegetable growth and an interposed layer of strengthening material. 4L. A diaphrag n for sound boxes composed of superposed Washed natural'films of vegetable growth and crossed as to their a a grain;

skin of the poplar tree in their natural state. I

6. A" dia'phragm for phonographs comprising superposed Washed films of the inner skin of the poplar tree in their natural state and a layer of Woven fabrlc. i

prising superposed Washed films of the inner bark of the poplar tree in their natural state and an interposed layer of voven tabric and a binding material.

9. An acoustic diaphragm composd of Washed'natural films of-vegetable'growth. 10, An acoustic diaphragm composed of Washed natural films ofv Vegetable growth artificially joined in a unitary structure.

Signed 'at 'New York in the county of New York and State of New York this 29th r 7 day of October A. D. 1917. diaphragm for sound boxes comprisw ing superposed Washed-films of the inner Vitne'sses C. W ESLEY POMEROY, THOS. W. BROWN.

WILLIAM H. DRU IiZlMOND; 

